Volcanic ash from Klyuchevskoy volcano observed at 6 100 m (20 000 feet) a.s.l., Russia

Volcanic ash from Klyuchevskoy volcano in Russia was observed at 6 100 m (20 000 feet) at 20:00 UTC on October 14, 2025. The advisory was issued by the Tokyo VAAC at 20:32 UTC on the same date.

According to the advisory, volcanic ash was observed between the surface and 6 100 m (20 000 feet), extending northeast. The observation was supported by data from Himawari-8 satellite and UHPP. The ash cloud was moving northeast at approximately 19 km/h (12 mph). Some of the ash was obscured by meteorological clouds. No Aviation Color Code was stated in this advisory. It was also noted that VAAC Anchorage issued a separate advisory for volcanic ash at 7 000 m (23 000 feet) over or near the VAAC Tokyo area.

The Smithsonian / USGS Weekly Volcanic Activity Report for September 24-30, 2025, stated that wind was no longer resuspending ash previously deposited on the north flank of Klyuchevskoy, and only fumarolic emissions were observed. The Aviation Color Code was lowered to Green on September 25, 2025.

Klyuchevskoy is a stratovolcano and the highest volcano in Eurasia, rising to 4 754 m (15 597 feet). It is known for frequent explosive eruptions, producing ashfall, lava flows, and pyroclastic flows. The nearest settlements, such as Klyuchi and Kozyrevsk, are located within 50 km (31 miles) of the volcano and could be affected by ashfall and related hazards during eruptive activity.